ORIGINAL ARTICLE Cyclodextrins as cosmetic delivery systems Marisanna Centini Æ Maria Maggiore Æ Mario Casolaro Æ Marco Andreassi Æ Roberto Maffei Facino Æ Cecilia Anselmi Received: 15 May 2006 / Accepted: 20 October 2006 / Published online: 18 January 2007 Ó Springer Science+Business Media B.V. 2007 Abstract Aim of this work was the study of ferulic acid/cyclodextrin (CD) association complexes. Ferulic acid (FA) is a compound well-known as antioxidant and photoprotective agent (approved in Japan as sun- screen). Notwithstanding this, it is poorly suited for cosmetic applications because it undergoes functional and organoleptic modifications, when it is exposed to air, UV-light and heat. For this reason we prepared a set of FA/CD complexes with the aim to improve its physico-chemical stability. The inclusion complexes were characterized by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and nuclear magnetic resonance ( 1 H-NMR). The FA/a-CD complex showed the most promising properties (high association con- stant, high degree of photostability, slower FA release) as sunscreen delivery system. Keywords CDs inclusion complexes Á Ferulic acid Á Photostability Á Radical scavenging activity Á Release Introduction In the formulation of cosmetic products [1], active ingredients and a variety of other compounds give to the products their physical form and may control the delivery of the active ingredient(s). The cosmetic industry is constantly looking for new and effective products endowed with a satisfactory biological activity and an efficient delivery on the skin. In this context, several technological advances have been made in the development of new formulations for cosmetic delivery. These new technologies control the rate and target of delivery and the duration of activity. The cosmetic delivery systems can be divided into three classes: vesicular (liposomes and niosomes), molecular (cyclodextrins), and particulate (microcap- sules and matrix particles) [2]. Aim of the study was to improve the physico- chemical stability of the well-known phenolic com- pound ferulic acid (FA) [3–7] using different cyclodextrins (a-, b-, c-CD) at the light of its possible use as sunscreen. FA is a polyphenolic derivative with interesting sunscreen properties but it is poorly suited for cosmetic use since it undergoes degradation when exposed to light, air and heat [3]. In this paper, we report the results relative to different FA/CD inclusion complexes, with particular emphasis on the FA/a-CD inclusion complex, since in a previous thermodynamic study [8] it has been shown to possess a high degree of stability. In addition, we have tested the release and the Oxy- gen Radical Antioxidant Capacity (ORAC assay) of this promising inclusion complex in respect to free FA. M. Centini Á M. Maggiore Á M. Andreassi Á C. Anselmi (&) Centro Interdipartimentale di Scienza e Tecnologia Cosmetiche, University of Siena, Via della Diana 2, 53100 Siena, Italy e-mail: anselmic@unisi.it M. Casolaro Dipartimento di Scienze e Tecnologie Chimiche e dei Biosistemi, University of Siena, Via Aldo Moro, 53100 Siena, Italy R. Maffei Facino Istituto di Chimica Farmaceutica e Tossicologica, Facolta ` di Farmacia, University of Milano, Viale Abruzzi 42, 20131 Milano, Italy 123 J Incl Phenom Macrocycl Chem (2007) 57:109–112 DOI 10.1007/s10847-006-9212-0